Method for preparing a high heat resistant epoxy resin composition comprising quinoxalinium salt containing benzyl group

ABSTRACT

A method for preparing a high-heat-resistant-epoxy-resin composition which comprises adding, as catalytic curing agent, a quinoxalinium salt having a benzyl group to difunctional and multifunctional epoxy resin and thermoset resin having a similar structure. The epoxy-resin composition obtained by the present invention is excellent in its impregnating property, processability, impact resistance, drug resistance, electric-insulating property, and adhesiveness.

FIELD OF THE INVENTION

The present invention relates to a method for preparing ahigh-heat-resistant-epoxy-resin composition. More specifically, itrelates to a method for preparing an epoxy-resin composition whichameliorates or prevents the decrease of the thermal property of epoxymonomer when the epoxy is cured and which can be used at hightemperatures by using a quinoxalinium salt having a benzyl group as apotential catalytic curing agent capable of curing in a short periodunder conditions allowing good processability.

BACKGROUND OF THE INVENTION

It is well known that epoxy-resin, one of the thermoset resins, is ahigh-molecular-weight material having good heat resistance, mechanicalproperties, electric insulating properties, adhesiveness and weatherresistance; and epoxy resin is used as paint, an electric insulatingmaterial, a stabilizer for vinyl chloride, a coating and a matrix resinof fiber-reinforced complex material. It may fairly be said that thesewidely varying industrial applications of epoxy resin have resulted fromthe development of curing technology; and, thus, the effect of thecuring agent on epoxy resin is enormous.

Specifically, epoxy resin requires the use of a curing agent in order tocreate a three-dimensional net structure; and, therefore, the heatresistance and the final mechanical properties of the epoxy resin may bedifferent depending on the nature of this curing agent. Curing agentshaving components harmful to the human body (e.g., amine compounds) arefrequently used, which results in many problems. The use of such curingagents in combination with additives such as accelerators, plasticizers,fillers, mold-releasing agents, flame retardants, diluents and dyeslargely reduces the physical properties of the epoxy resin.

Further, the use of a curing agent comprising an amine (e.g., DDS:4,4-diaminodiphenylsulfone) may result in decreased processability dueto its high viscosity; and, thus, the production of molded productsusing such a curing agent becomes very difficult.

Recently, the development of high-quality integrated circuits in thecourse of the development of the electric and electronic industries hasrequired the development of materials for high-performance print-circuitsubstrates. Furthermore, materials capable of high-density wiring havingexcellent electric insulating properties, dielectric properties anddimensional stability have been constantly requested. For instance,materials with heat resistance that does not change above approximately180° C. are are in demand for the large-plate-display industry forapplications such as LCD (Liquid Crystal Displays), FED (Field EmissionDisplays), and PDP (Plasma Display Panels), which are referred to asnext generation industries. However, this demand is not being satisfiedbecause the existing epoxy resins have unreliable resistance to hightemperatures; and the cost of high-heat-resistant epoxy resins (such asFR-5, bismaleimide triazine resin, or polyimide resin) is still high.The present invention meets the technical demands of industry and solvesor ameliorates the problems of the prior art.

SUMMARY

It is an object of the present invention to provide a method forpreparing an epoxy resin composition which increases the physicalproperties of epoxy resin itself with the use of a small amount ofcatalytic curing agent, and optionally, which ensures high heatresistance by the addition of an existing high-heat-resistant curingagent or which alternatively increases physical properties such as heatresistance by the addition of other thermoset and thermoplastic matrixresin in the course of the production of the epoxy-resin composition.

This object can be attained by adding a quinoxalinium salt having abenzyl group as a catalytic curing agent to difunctional andmultifunctional epoxy resin and thermoset resin having a similarstructure.

Other objects and advantages will be apparent from the followingdescription to those who have ordinary skill in the art.

DETAILED DESCRIPTION

It has now been found that the addition of a quinoxalinium salt having abenzyl group to difunctional and multifunctional epoxy resin andthermoset resins of a similar structure can primarily formthree-dimensional net-structure precursor material and show heatstability in cases of increased curing temperature, thereby causing theresulting curable composition to show heat resistance approximately 30%to approximately 300% higher than that of the existing thermoset resin.Thermoset resins of a similar structure comprise a difunctionalthermoset resin or a multifunctional thermoset resin.

In addition, it has also been found that in curing by using just acuring agent prepared according to the present invention without usingany other existing curing agents, the viscosity of the resin atapproximately 60 to approximately 180° C. is very low--approximatelylike water--and the impregnation properties and processability of theresin are excellent.

In the curing technology of the existing epoxy resin and similar curableresin, the use of catalytic curing agent prepared according to thepresent invention can reduce detrimental effects on the human body andthe environment due to the use of amine-type curing agents.

Moreover, when a quinoxalinium salt having benzyl group according to thepresent invention is used together with an existing amine-type curingagent, a thermoset epoxy resin composition and resin composition of asimilar structure having high heat resistance, high impact resistance,high drug resistance, high electric insulating property and highadhesiveness can be obtained.

When approximately 0.01% to approximately 50.5% of quinoxalinium salthaving a benzyl group according to the present invention is addedwithout the existing curing agent, the autocatalytic reaction of theepoxy resin and the resin having a similar structure can be accelerated.

As a quinoxalinium salt having a benzyl group according to the presentinvention is added, the epoxy resin and the resin having a similarstructure have a constant or generally constant linear or generallylinear expansion coefficient at approximately 60° C. to approximately360° C., showing heat stability at that temperature; and, thus, themechanical property of the resins is maintained.

As a quinoxalinium salt having a benzyl group according to the presentinvention is added, the thermal decomposition temperature begins atapproximately 250° C. or more, depending on whether the epoxy isdifunctional or multifunctional.

The viscosity of the resin surprisingly increases at a certain point togive a solid material. However, during the reaction period at thattemperature, shrinkage of the resin, which was shown in existing epoxyresin and resin of similar structures, does not occur. On the contrary,an increase of the volume from approximately 0.01 to approximately 15%occurs and provides satisfactory molding conditions, thereby rendering agood dimensional property in the processing production.

The catalyst used as a curing agent in the present invention is aquinoxalinium salt having a benzyl group, namely, N-benzyl quinoxaliniumsalt known for having high activity, preferably N-benzyl quinoxaliniumhexafluoroantimonate. Thus, in one embodiment, the present inventionincludes a catalytic curing agent for preparing ahigh-heat-resistant-epoxy-resin composition, the curing agentcomprising, consisting of, or consisting essentially of a quinoxaliniumsalt having a benzyl group. More specifically, the curing agentcomprises, consists of, or consists essentially of N-benzylquinoxalinium salt. More specifically, the curing agent comprises,consists of, or consists essentially of N-benzyl quinoxalinium salt,wherein the N-benzyl quinoxalinium salt is N-benzyl quinoxaliniumhexafluoroantimonate.

The N-benzyl quinoxalinium hexafluoroantimonate is prepared by theKorean Research Institute of Chemical Technology by reacting benzylbromide with quinoxaline at room temperature, filtering the resultinginsoluble benzyl quinoxalinium salt, dissolving it in aqueous solution,adding NaSbF₆ to the solution, filtering the resulting white solid, andpurifying and drying via recrystallization from methanol. The resultingcompound is represented by the following formula ##STR1## wherein R is ahydrogen atom or an alkoxy group.

The N-benzyl-quinoxalinium-hexafluoroantimonate according to the presentinvention has the following approximate physical properties:

melting point: 146.1-148.2° C.

¹ H NMR (acetone-d₆):

δ=9.82-9.89 (d, 1H, Qu)

9.61-9.65 (d, 1H, Qu)

8.82-8.88 (d, 1H, Qu)

8.59-8.65 (d, 1H, Qu)

8.32-8.46 (t, 2H, Qu)

7.62-7.69 (d, 2H, Ph)

7.49-7.55 (d, 3H, Ph)

6.66 (s, 2H, --CH₂ --)

IR (KBr) v=3098, 1514, 1359, 1073, 767, 667 cm-¹ ; C₁₅ H₁₃ N₂ SbF₆=Calculated: C: 39.39% H: 2.84% N: 6.13% ; Found: C: 39.69% H: 2.86% N:6.16%.

The catalytic curing agent according to the present invention has alonger storage effect on epoxy resin than the one prepared by using theexisting amine type curing agent, initiates the curing reaction in ashort time, and has a low hygroscopic property and excellent waterresistance and drug resistance.

As mentioned above, since it is possible to carry out the curingreaction using only a catalytic curing agent according to the presentinvention without forming noxious gases such as amine during the curingreaction, the curing agent according to the present invention isexpected to act as an environmentally-clean additive for providingelectrical and electronic parts, print-substrate raw materials,electrical insulating materials, adhesive and fiber-reinforced prepregs.Optionally, the catalytic curing agent of the present invention may beused as a curing accelerator in resin formulation, which is used asflame retardant, extender, antistatic agent, surfactant, pigment, paint,or dye.

The present invention will now be explained in more detail withreference to the following examples and comparative examples, but it isto be understood that the present invention is not restricted theretoand various modifications are possible within the scope of theinvention.

EXAMPLE 1

Approximately 1% by weight of the catalytic curing agent according tothe present invention was added to multifunctional epoxy resin YH-300(Kukdo Chemical Co., Ltd.) and was allowed to stand at approximately 25°C. under sunlight for one week to give a hard, resilient, solidmaterial. The analysis to determine mass change was carried out byThermo-Gravimetric Analysis (TGA) under a nitrogen atmosphere in anamount of approximately 50 cm³ /minute while keeping the rate oftemperature elevation to approximately 10° C./minute. The thermaldecomposition began at approximately 262° C. Considering the fact thatthe heat resistance of multifunctional epoxy resins such astrifunctional and tetrafunctional epoxy resin is approximately 150 to250° C., an increase in heat resistance of about 30 to about 75% wasshown.

In order to check and analyze the above result, a sample obtained byadding curing agent to the resin used in this example (YH-300) andmaintained at approximately 130° C. for about 10 minutes was analyzed byusing NMR and an FTIR analyzer; and it was found that a new material wasformed starting from the original composition.

The material is referred to as a precursor material for forming finalcured product from epoxy resin (YH-300). It was noted that a precursoras a cured product having thermal stability at a high temperature waspreviously formed in the course of the curing reaction, and thussatisfied the final curing condition at a higher temperature andresulted in a remarkably improved thermal decomposition startingtemperature.

EXAMPLE 2

Approximately 1% by weight of the catalytic curing agent according tothe present invention was added to difunctional epoxy resin YD-128(Kukdo Chemical Co., Ltd.) having intermediate viscosity and was allowedto stand at approximately 25° C. under sunlight for three days to give ahard, resilient, solid material. The thermal decomposition began atapproximately 350° C., which was determined by the same method as inExample 1. Considering the fact that the heat resistance ofmultifunctional epoxy resins such as difunctional epoxy resin isapproximately 90 to approximately 150° C., an increase in heatresistance of about 130 to about 290% was shown.

In order to check and analyze the above result, a sample obtained byadding curing agent to the resin used in this example (YD-128) andmaintained at approximately 130° C. for about 10 minutes was analyzed byusing NMR and an FTIR analyzer; and it was found that a new material wasformed starting from the original composition.

The material is referred to as a precursor material for forming final acured product from epoxy resin (YD-128). It was noted that a precursoras a cured product having thermal stability at a high temperature waspreviously formed in the course of the curing reaction, and thussatisfied the final curing condition at a higher temperature andresulted in a remarkably improved thermal decomposition startingtemperature.

EXAMPLE 3

Approximately 1% by weight of the catalytic curing agent according tothe present invention was added to difunctional epoxy resin LY-556(manufactured by Ciba-Geigy AG) and was allowed to stand atapproximately 170° C. for approximately one hour to give a resilientpolymer. The thermal decomposition began at approximately 337° C., whichwas determined by the same method as in Example 1. Considering the factthat the heat resistance of multifunctional epoxy resins such asdifunctional epoxy resin is approximately 90 to approximately 150° C.,an increase in heat resistance of about 120 to about 270% was shown.

In order to check and analyze the above result, a sample obtained byadding curing agent to the resin used in this example (LY-556) andmaintained at approximately 130° C. for about 10 minutes was analyzed byusing NMR and an FTIR analyzer; and it was found that a new material wasformed starting from the original composition.

The material is referred to as a precursor material for forming finalcured product from epoxy resin (LY-556). It was noted that a precursoras a cured product having thermal stability at a high temperature waspreviously formed in the course of the curing reaction, and thussatisfied the final curing condition at a higher temperature andresulted in a remarkably improved thermal decomposition startingtemperature.

EXAMPLE 4

Approximately 1% by weight of the catalytic curing agent according tothe present invention was added to the difunctional epoxy resin LY-5082(manufactured by Ciba-Geigy AG) and was allowed to stand atapproximately 170° C. for about one hour to give a resilient polymer.The thermal decomposition began at approximately 284° C., which wasdetermined by the same method as in Example 1. Considering the fact thatthe heat resistance of multifunctional epoxy resins such as difunctionalepoxy resin is approximately 90 to approximately 150° C., an increase inheat resistance of about 90 to about 210% was shown.

In order to check and analyze the above result, a sample obtained byadding curing agent to the resin used in this example (LY-5082) andmaintained at approximately 130° C. for about 10 minutes was analyzed byusing NMR and an FTIR analyzer; and it was found that a new material wasformed starting from the original composition.

The material is referred to as a precursor material for forming finalcured product from epoxy resin (LY-5082). It was noted that a precursoras a cured product having thermal stability at a high temperature waspreviously formed in the course of the curing reaction, and thussatisfied the final curing condition at a higher temperature andresulted in a remarkably improved thermal decomposition startingtemperature.

COMPARATIVE EXAMPLE 1

Approximately 1% by weight of the catalytic curing agent according tothe present invention was added to the difunctional epoxy resin LY-556(manufactured by Ciba-Geigy AG) used in Example 3 and was allowed tostand at approximately 170° C. for about one hour to give a resilientpolymer. The analysis to determine thermal capacity and enthalpy changewas carried out by Differential Scanning Analysis (DSC) under a nitrogenatmosphere in an amount of approximately 50 cm³ /minute while keepingthe temperature elevating rate at approximately 10° C./minute. Athree-dimensional net structure was formed around the thermaldecomposition starting at a temperature of about 200° C. When observingthe thermoset reaction of a typical epoxy resin, it was noted that acomplete curing proceeded after a three-dimensional net structure wasformed with the increase of temperature, while the thermal decompositionreaction occurred as the temperature continuously increased. This resultshows that the heat resistance of the epoxy resin was considerablyimproved as shown in Example 3.

COMPARATIVE EXAMPLE 2

Approximately 1% by weight of the catalytic curing agent according tothe present invention was added to trifunctional epoxy resin MY0510(manufactured by Ciba-Geigy AG) and tetrafunctional epoxy resin MY721(manufactured by Ciba-Geigy AG) and was allowed to stand atapproximately 170° C. or approximately 190° C. for about one hour togive a liquid. As a result of observing by a method as in ComparativeExample 1, MY0510 showed a three-dimensional net structure around 283°C.; and the thermal decomposition happened immediately. In the case ofMY721, a three-dimensional net structure was not formed; and only thethermal decomposition proceeded. When observing the thermoset reactionof a typical epoxy resin, once a three-dimensional net structure wasformed with the increase of temperature, the thermal decompositionreaction occurred as the temperature continuously increased. This resultshows that the catalytic curing agent improves the heat resistance ofthe epoxy resin having primarily linear structure.

COMPARATIVE EXAMPLE 3

Approximately 1% by weight of the catalytic curing agent according tothe present invention was added to the difunctional epoxy resin LY-5082(manufactured by Ciba-Geigy AG) used in Example 4 and was allowed tostand at approximately 170° C. for about one hour to give a polymer. Asa result of observing by a method as in Comparative Example 1, athree-dimensional net structure was formed at the thermal decompositionstarting temperature of around 193° C. When observing the thermosetreaction of a typical epoxy resin, once a three-dimensional netstructure was formed with the increase of temperature, the thermaldecomposition reaction occurred as the temperature continuouslyincreased. This result shows that the catalytic curing agent improvesthe heat resistance of the epoxy resin as shown in Example 4.

COMPARATIVE EXAMPLE 4

Approximately 1% by weight of the catalytic curing agent according tothe present invention was added to the difunctional epoxy resin LY-5082(manufactured by Ciba-Geigy AG) used in Example 4 and ComparativeExample 3 and was allowed to stand at approximately 170° C. for aboutone hour to give a polymer. The linear expansion coefficient accordingto the temperature was determined by using Thermo-Mechanical Analysis(TMA), which determines the change of the mechanical property under anitrogen atmosphere in an amount of approximately 50 cm³ /minute whilekeeping the rate of temperature elevation at approximately 10°C./minute. The coefficient showed a constant value, namely,approximately 1.779×10⁻⁴ K⁻¹ at approximately 100° C. to approximately250° C. This indicated that the epoxy resin had heat stability up toapproximately 250° C.; and its distinguishable decomposition temperaturewas much higher than that temperature, which was confirmed by comparingthe resulting data from Example 4 and Comparative Example 3.

COMPARATIVE EXAMPLE 5

Approximately 1% by weight of the catalytic curing agent according tothe present invention was added to the difunctional epoxy resin LY-556(manufactured by Ciba-Geigy AG) used in Example 3 and ComparativeExample 1 and was allowed to stand at approximately 170° C. for aboutone hour to give a polymer. As a result of a determination by RDA(Rheological Dynamic Analyser), which is capable of analyzing the changeof viscosity and the linear expansion coefficient according totemperature, we discovered that the viscosity of the resin decreasedapproximately to the level of water at around 140° C. The viscosityincreased drastically at around 190° C. as the temperature continuouslyincreased; and, thus, a high resilient solid material was obtained. Itis worth special mention that the volume shrinkage occurring in the caseof the curing reaction of the general epoxy resin was not found andinstead showed some volume increase.

COMPARATIVE EXAMPLE 6

Approximately 1% by weight of the catalytic curing agent according tothe present invention was added to the difunctional epoxy resin LY-5082(manufactured by Ciba-Geigy AG) used in Example 4 and ComparativeExamples 3 and 4 and was allowed to stand at approximately 170° C. forabout one hour to give a polymer. As a result of the same determinationas in Comparative Example 5, we discovered that the viscosity of theresin decreased approximately to the level of water at around 120° C.The viscosity of the resin increased drastically at around 190° C. asthe temperature continuously increased; and, thus, a high resilientsolid material was obtained. The volume shrinkage occurring in the caseof the curing reaction of the general epoxy resin was not found andinstead showed some volume increase.

The invention illustratively disclosed herein suitably may be practicedin the absence of any element which is not specifically disclosedherein. Thus, the invention may comprise, consist of, or consistessentially of the elements disclosed herein.

Although the present invention has been described in considerable detailwith reference to certain preferred embodiments, the spirit and thescope of the appended claims should not be limited to the description ofthe preferred embodiments contained herein.

What is claimed is:
 1. A method for preparing ahigh-heat-resistant-epoxy-resin composition, the method comprising thefollowing steps:(a) adding a catalytic curing agent to a difunctionalepoxy resin to yield a resin mixture having a temperature and aviscosity; (b) increasing the temperature of the resin mixture to atleast approximately 120° C. to yield a precursor material having aviscosity less than the viscosity of the resin mixture in step (a),wherein the precursor material has a temperature; (c) increasing thetemperature of the precursor material to at least approximately 170° C.to cure the precursor material to yield thehigh-heat-resistant-epoxy-resin composition;wherein the catalytic curingagent comprises N-benzyl-quinoxalinium-hexafluoroantimonate representedby the following formula ##STR2## wherein R is a hydrogen atom or analkoxy group.
 2. A method as claimed in claim 1 for preparing anepoxy-resin composition having high heat resistance, high impactresistance, high drug resistance, high electric insulating property andhigh adhesiveness, wherein the catalytic curing agent further comprisesan amine.
 3. A method as claimed in claim 1, wherein the catalyticcuring agent further comprises an amine curing agent.
 4. A method forpreparing a high-heat-resistant-epoxy-resin composition, the methodcomprising the following steps:(a) adding a catalytic curing agent to adifunctional epoxy resin to yield a resin mixture having a temperatureand a viscosity; (b) increasing the temperature of the resin mixture toat least approximately 120° C. to yield a precursor material having aviscosity less than the viscosity of the resin mixture in step (a),wherein the precursor material has a temperature; (c) increasing thetemperature of the precursor material to at least approximately 170° C.to cure the precursor material to yield thehigh-heat-resistant-epoxy-resin composition;wherein the catalytic curingagent consists essentially ofN-benzyl-quinoxalinium-hexafluoroantimonate represented by the followingformula ##STR3## wherein R is a hydrogen atom or an alkoxy group.
 5. Amethod as claimed in claim 1, wherein the curing agent further comprisesan amine.
 6. A method as claimed in claim 1, wherein in step (b) theviscosity of the precursor material is approximately equal to viscosityof water.
 7. A method as claimed in claim 1, wherein the precursormaterial has a volume and the high-heat-resistant-epoxy-resincomposition has a volume, and wherein the volume of thehigh-heat-resistant-epoxy-resin composition is greater than the volumeof the precursor material.
 8. A method as claimed in claim 7, whereinthe volume of the high-heat-resistant-epoxy-resin composition isapproximately 0.01% to approximately 15% greater than the volume of theprecursor material.
 9. A method as claimed in claim 1, wherein in step(b) the temperature of the resin mixture is increased to approximately120° C. to approximately 140° C.
 10. A method as claimed in claim 1,wherein in step (c) the temperature of the precursor material isincreased to approximately 170° C. to approximately 190° C.
 11. A methodas claimed in claim 9, wherein in step (c) the temperature of theprecursor material is increased to approximately 170° C. toapproximately 190° C.
 12. A method as claimed in claim 1, whereinthermal decomposition of the high-heat-resistant-epoxy-resin compositionbegins at approximately 250° C. or more.
 13. A method as claimed inclaim 1,wherein in step (b) the temperature of the resin mixture isincreased to approximately 120° C. to approximately 140° C.; wherein instep (c) the temperature of the precursor material is increased toapproximately 170° C. to approximately 190° C.; and wherein theprecursor material has a volume and the high-heat-resistant-epoxy-resincomposition has a volume, and wherein the volume of thehigh-heat-resistant-epoxy-resin composition is greater than the volumeof the precursor material.
 14. A method as claimed in claim 3,wherein instep (b) the temperature of the resin mixture is increased toapproximately 120° C. to approximately 140° C.; wherein in step (c) thetemperature of the precursor material is increased to approximately 170°C. to approximately 190° C.; and wherein the precursor material has avolume and the high-heat-resistant-epoxy-resin composition has a volume,and wherein the volume of the high-heat-resistant-epoxy-resincomposition is greater than the volume of the precursor material.
 15. Ahigh-heat-resistant-epoxy-resin composition made by the method claimedin claim
 1. 16. A high-heat-resistant-epoxy-resin composition as claimedin claim 15, wherein the precursor material has a volume and thehigh-heat-resistant-epoxy-resin composition has a volume, and whereinthe volume of the high-heat-resistant-epoxy-resin composition is greaterthan the volume of the precursor material.
 17. Ahigh-heat-resistant-epoxy-resin composition as claimed in claim 16,wherein the volume of the high-heat-resistant-epoxy-resin composition isapproximately 0.01% to approximately 15% greater than the volume of theprecursor material.
 18. A high-heat-resistant-epoxy-resin composition asclaimed in claim 15, wherein thermal decomposition of thehigh-heat-resistant-epoxy-resin composition begins at approximately 250°C. or more.
 19. A high-heat-resistant-epoxy-resin composition as claimedin claim 16, wherein thermal decomposition of thehigh-heat-resistant-epoxy-resin composition begins at approximately 250°C. or more.
 20. A high-heat-resistant-epoxy-resin composition made bythe method claimed in claim
 13. 21. A method for preparing ahigh-heat-resistant-epoxy-resin composition, the method comprising thefollowing steps:(a) adding a catalytic curing agent to a difunctionalepoxy resin to yield a resin mixture having a temperature and aviscosity; (b) increasing the temperature of the resin mixture to yielda precursor material having a viscosity approximately equal to viscosityof water, wherein the precursor material has a temperature; (c)increasing the temperature of the precursor material to cure theprecursor material to yield the high-heat-resistant-epoxy-resincomposition;wherein the catalytic curing agent comprisesN-benzyl-quinoxalinium-hexafluoroantimonate represented by the followingformula ##STR4## wherein R is a hydrogen atom or an alkoxy group.
 22. Amethod as claimed in claim 21, wherein the catalytic curing agentfurther comprises an amine.
 23. A method as claimed in claim 21, whereinthe catalytic curing agent further comprises an amine curing agent. 24.A method as claimed in claim 21, wherein the precursor material has avolume and the high-heat-resistant-epoxy-resin composition has a volume,and wherein the volume of the high-heat-resistant-epoxy-resincomposition is greater than the volume of the precursor material.
 25. Amethod as claimed in claim 24, wherein the volume of thehigh-heat-resistant-epoxy-resin composition is approximately 0.01% toapproximately 15% greater than the volume of the precursor material. 26.A method as claimed in claim 21, wherein thermal decomposition of thehigh-heat-resistant-epoxy-resin composition begins at approximately 250°C. or more.
 27. A high-heat-resistant-epoxy-resin composition made bythe method claimed in claim
 21. 28. A high-heat-resistant-epoxy-resincomposition as claimed in claim 27, wherein the precursor material has avolume and the high-heat-resistant-epoxy-resin composition has a volume,and wherein the volume of the high-heat-resistant-epoxy-resincomposition is greater than the volume of the precursor material.
 29. Ahigh-heat-resistant-epoxy-resin composition as claimed in claim 28,wherein the volume of the high-heat-resistant-epoxy-resin composition isapproximately 0.01% to approximately 15% greater than the volume of theprecursor material.
 30. A high-heat-resistant-epoxy-resin composition asclaimed in claim 27, wherein thermal decomposition of thehigh-heat-resistant-epoxy-resin composition begins at approximately 250°C. or more.
 31. A high-heat-resistant-epoxy-resin composition as claimedin claim 28, wherein thermal decomposition of thehigh-heat-resistant-epoxy-resin composition begins at approximately 250°C. or more.
 32. A method as claimed in claim 21, wherein the temperatureof the resin mixture in step (b) is increased to at least approximately120° C.
 33. A method as claimed in claim 21, wherein the temperature ofthe precursor material in step (c) is increased to at leastapproximately 170° C.
 34. A method as claimed in claim 1, wherein thecatalytic curing agent further comprises 4,4-diaminodiphenylsulfone. 35.A method as claimed in claim 21, wherein the catalytic curing agentfurther comprises 4,4-diaminodiphenylsulfone.